Conventionally, from the viewpoint of improving a fuel consumption performance of vehicle such as an automobile, weight saving of a wire harness (W/H) that is configured of a group of a plurality of electric wires is required strongly. As the weight saving of a wire harness, weight saving of a conductor (core wire) itself of an electric wire to be used for the wire harness is examined. For example, a wire harness using an aluminum-based metal having a specific gravity that is lighter than that of a copper-based material (in particular, annealed copper material) as a material of the conductor of an electric wire is disclosed (for example, see Patent Literature 1).
Specifically, the electric wire is configured of a low-current electric wire used for a power source circuit, a high-current/ground electric wire used for a high-current power source circuit and a ground circuit and allowing a current larger than that of the first electric wire to flow, and a signal electric wire used for a signal circuit.
The low-current electric wire and the signal electric wire are formed of an aluminum electric wire in which the conductor is made of aluminum or an aluminum alloy and the high-current/ground electric wire is formed of a copper electric wire in which the conductor is made of copper or a copper alloy. Hereby, when comparing with the case where all the conductors of the low-current electric wire, the high-current/ground electric wire and the signal electric wire are formed of a copper electric wire, weight saving can be achieved.